title: Gene expression in hippocampus as a function of differential trait anxiety levels in genetically heterogeneous NIH-HS rats.
abstract: To identify genes involved in the development/expression of anxiety/fear, we analyzed the gene expression profile in the hippocampus of genetically heterogeneous NIH-HS rats. The NIH-HS rat stock is a unique genetic resource for the fine mapping of quantitative trait loci (QTLs) to very small genomic regions, due to the high amount of genetic recombinants accumulated along more than 50 breeding generations, and for the same reason it can be expected that those genetically heterogeneous rats should be especially useful for studying differential gene expression as a function of anxiety, fearfulness or other complex traits. We selected high- and low-anxious NIH-HS rats according to the number of avoidance responses they performed in a single 50-trial session of the two-way active avoidance task. Rats were also tested in unconditioned anxiety/fearfulness tests, i.e. the elevated zero-maze and a "novel-cage activity" test. Three weeks after behavioral testing, the hippocampus was dissected and prepared for the microarray study. There appeared 29 down-regulated and 37 up-regulated SNC-related genes (fold-change>|2.19|, FDR<0.05) in the "Low-anxious" vs. the "High-anxious" group. Regression analyses (stepwise) revealed that differential expression of some genes could be predictive of anxiety/fear responses. Among those genes for which the present results suggest a link with individual differences in trait anxiety, nine relevant genes (Avpr1b, Accn3, Cd74, Ltb, Nrg2, Oprdl1, Slc10a4, Slc5a7 and RT1-EC12), tested for validation through qRT-PCR, have either neuroendocrinological or neuroinmunological/inflammation-related functions, or have been related with the hippocampal cholinergic system, while some of them have also been involved in the modulation of anxiety or stress-related (neurobiological and behavioral) responses (i.e. Avpr1b, Oprdl1). The present work confirms the usefulness of NIH-HS rats as a good animal model for research on the neurogenetic basis or mechanisms involved in anxiety and/or fear, and suggest that some MHC-(neuroinmunological/inflammation)-related pathways, as well as the cholinergic system within the hippocampus, may play a role in shaping individual differences in trait anxiety.
authors.affiliation: Medical Psychology Unit, Department of Psychiatry & Forensic Medicine, Institute of Neurosciences, School of Medicine, Autonomous University of Barcelona, Barcelona, Spain.
authors.forename: Sira
authors.initials: S
authors.lastname: Díaz-Morán
authors.forename: Marta
authors.initials: M
authors.lastname: Palència
authors.forename: Carme
authors.initials: C
authors.lastname: Mont-Cardona
authors.forename: Toni
authors.initials: T
authors.lastname: Cañete
authors.forename: Gloria
authors.initials: G
authors.lastname: Blázquez
authors.forename: Esther
authors.initials: E
authors.lastname: Martínez-Membrives
authors.forename: Regina
authors.initials: R
authors.lastname: López-Aumatell
authors.forename: Marta
authors.initials: M
authors.lastname: Sabariego
authors.forename: Rocío
authors.initials: R
authors.lastname: Donaire
authors.forename: Ignacio
authors.initials: I
authors.lastname: Morón
authors.forename: Carmen
authors.initials: C
authors.lastname: Torres
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Martínez-Conejero
authors.forename: Adolf
authors.initials: A
authors.lastname: Tobeña
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Esteban
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernández-Teruel
mesh_terms: D062565:Acid Sensing Ion Channels / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics / Q000378:metabolism; D001007:Anxiety / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D001362:Avoidance Learning / Q000502:physiology; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology; D005786:Gene Expression Regulation / Q000235:genetics*; D018740:Genetic Heterogeneity; D006624:Hippocampus / Q000378:metabolism*; D006649:Histocompatibility Antigens / Q000235:genetics / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism; D053308:Lymphotoxin-beta / Q000235:genetics / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D029363:Organic Anion Transporters, Sodium-Dependent / Q000235:genetics / Q000378:metabolism; D050480:Plasma Membrane Neurotransmitter Transport Proteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017483:Receptors, Vasopressin / Q000235:genetics / Q000378:metabolism; D027981:Symporters / Q000235:genetics / Q000378:metabolism
chemical_list: C568269:ASIC3 protein, rat; D062565:Acid Sensing Ion Channels; D000944:Antigens, Differentiation, B-Lymphocyte; D006649:Histocompatibility Antigens; D000949:Histocompatibility Antigens Class II; C505888:Ltb protein, rat; D053308:Lymphotoxin-beta; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; C491452:Nrg2 protein, rat; D029363:Organic Anion Transporters, Sodium-Dependent; D050480:Plasma Membrane Neurotransmitter Transport Proteins; D017483:Receptors, Vasopressin; D027981:Symporters; C038353:histocompatibility antigens RT, rat; C045084:invariant chain; C071908:sodium-bile acid cotransporter; C075746:Slc6a8 protein, rat
keywords: Anxiety; Fear; Gene expression; Genetically heterogeneous rats; Hippocampus